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A novel oxygen evolution reaction (OER) catalyst (3D S235-P steel) based on steel S235 substrate has been successfully prepared via a facile one-step surface modification. The standard Carbon Manganese steel was phosphorizated superficially leading to the formation of a unique 3D interconnected nanoporous surface with high specific area which facilitates the electrocatalytically initiated oxygen evolution reaction. The prepared 3D S235-P steel exhibits enhanced electrocatalytic OER activities in alkaline regime confirmed by a low overpotential ({\eta}=326 mV at j=10 mA cm-2) and a small Tafel slope of 68.7 mV dec-1. Moreover, the catalyst was found to be stable under long-term usage conditions functioning as oxygen evolving electrode at pH 13 as evidenced by the sufficient charge to oxygen conversion rate (Faradaic efficiency: 82.11% and 88.34% at 10 mA cm-2 and 5 mA cm-2, respectively). In addition, it turned out that the chosen surface modification renders steel S235 into an OER electrocatalyst sufficiently and stable to work in neutral pH condition. Our investigation revealed that the high catalytic activities are likely to stem from the generated Fe/(Mn) hydroxide/oxo-hydroxides generated during the OER process. The phosphorization treatment is therefore not only an efficient way to optimize the electrocatalytic performance of standard Carbon-Manganese steel, but also enables for the development of low cost and abundant steels in the field of energy conversion., Comment: ChemSusChem, 2018, published online

We have investigated PLLA crystallization in lamellae-forming PS-b-PLLA confined to straight cylindrical nanopores under weak confinement (nanopore diameter D / equilibrium PS-b-PLLA period L0 larger than 4.8). Molten PS-b-PLLA predominantly forms concentric lamellae along the nanopores, but intertwined helices occur even for D/L0 = 7.3. Quenching PS-b-PLLA melts below TG(PS) results in PLLA cold crystallization strictly confined by the vitrified PS domains. Above TG(PS), PLLA crystallization is templated by the PS-b-PLLA melt domain structure in the nanopore centers, while adsorption on the nanopore walls stabilizes the outermost cylindrical PS-b-PLLA shell. In between, the nanoscopic PS-b-PLLA melt domain structure apparently ripens to reduce frustrations transmitted from the outermost immobilized PS-b-PLLA layer. The onset of PLLA crystallization catalyzes the ripening while transient ripening states are arrested by advancing PLLA crystallization. Certain helical structure motifs persist PLLA crystallization even if PS is soft. The direction of fastest PLLA crystal growth is preferentially aligned with the nanopore axes to the same degree as for PLLA homopolymer, independent of whether PS is vitreous or soft.

A top-down approach, i.e., creating small particles by mechanical force starting from bulk materials, probably presents the most logical approach to particle size reduction and, therefore, top-down techniques are among the first to achieve small particles. A new solvent-free, amazingly simple approach is reported, suitable to achieve nanoparticles and sub-micro particles.

Electrochemical behaviour of N-bromosuccinimide (NBS, mp 174 ºC) was investigated in 1,1,1,3,3,3-hexafluoropropan-2-ol (HFP) by cyclic and pulsed voltammetry at platinum electrode. The cyclic voltammetric response was characterized by an irreversible reduction peak at around 0.7 V vs. SCE, and an anodic peak at about 0.1 V on reverse sweep. The possible mechanism for electro-reduction of NBS was outlined. In case of normal pulse voltammetry, a well-defined sigmoid-shaped curve was obtained. An increase in step time resulted in a significant cathodic shift. Differential pulse voltammetric response was consistent with the normal pulse behaviour, and featured a single peak centered at about 0.88 V. Linear variation of summit current with pulse height was observed.

We have investigated PLLA crystallization in lamellae-forming PS-b-PLLA confined to straight cylindrical nanopores under weak confinement (nanopore diameter D/equilibrium PS-b-PLLA period L0 ≥ 4.8). Molten PS-b-PLLA predominantly forms concentric lamellae along the nanopores, but intertwined helices occur even for D/L0 ≈ 7.3. Quenching PS-b-PLLA melts below TG(PS) results in PLLA cold crystallization strictly confined by the vitrified PS domains. Above TG(PS), PLLA crystallization is templated by the PS-b-PLLA melt domain structure in the nanopore centers, while adsorption on the nanopore walls stabilizes the outermost cylindrical PS-b-PLLA shell. In between, the nanoscopic PS-b-PLLA melt domain structure apparently ripens to reduce frustrations transmitted from the outermost immobilized PS-b-PLLA layer. The onset of PLLA crystallization catalyzes the ripening while transient ripening states are arrested by advancing PLLA crystallization. Certain helical structure motifs persist PLLA crystallization even if PS is soft. The direction of fastest PLLA crystal growth is preferentially aligned with the nanopore axes to the same degree as for PLLA homopolymer, independent of whether PS is vitreous or soft.

Linear sweep voltammetry of N-bromosuccinimide at glassy carbon electrode in aqueous nitrate solution yielded a single, irreversible reduction wave. The cathodic peak current showed linear variation with concentration of N-bromosuccinimide. The reduction wave was simulated and kinetic parameters evaluated. Pulsed (differential and normal) voltammetric techniques are explored for determination of N-bromosuccinimide

Electrochemical simulation of the cyclic voltammogram of a 2,6- di-methyl-4-(diphenylmethylene)-2,5-cyclohexadien-1-one in DMSO/tetra-n-butylammonium hexafluorophosphate at a mercury cathode was carried out using two shareware simulation programs; CVSIM and ESP 2.4. Two cathodic and two anodic peaks were analyzed. 3,5-Bis(1,1-dimethylethyl)-4-oxo-2,5-cyclohexadienylideneacetonitrile, is an electron acceptor. Simulation of cyclic voltammogram of 3,5-bis(1,1-dimethylethyl)-4- oxo-2,5-cyclohexadienylideneacetonitrile, in acetonitrile at platinum electrode was carried out, and a scheme was suggested to obtain the heterogeneous rate constants for electron transfer. The results of simulations based on two shareware programs were generally consistent with theoretical and experimental work (3). Steady-state voltammetry was used to measure the heterogeneous electron-transfer rates for the reduction of quinones to determine the dependence of ko on molecular size, according to Marcus theory. This dependence was then used to predict the electron- transfer rate constants of related quinones, and the predictions were compared to experimental measurements (4).

Whereas reductive voltammetry of 1-bromopyrrolidin-2,5-dione (N-Bromosuccinimide), or SBr has been extensively studied in non-aqueous systems, relatively few papers have dealt with its electro-reduction in aqueous solutions. This paper describes voltammetry of 1-bromopyrrolidin-2,5-dione at platinum electrode in aqueous nitrate solution. The electrochemical reduction of N-chlorosuccinimide in acetonitrile at a platinum cathode parallels the reductions of N-bromosuccinimide. The overall n-value is 1; the succinimide anion, generated by a two electron reduction of N-chlorosuccinimide, is an intermediate; homogeneous electron transfer from the succinimide anion to N- chlorosuccinimide generates the succinimidyl radical, which is the precursor for the other products formed. The reduction of N-chlorosuccinimide by the succinimide anion, added, as a quaternary ammonium succinimide in a homogenous chemical system is significantly different from the comparable reaction with N-bromosuccinimide. Rate constants for the pertinent reactions were measured, and the reaction mechanism was proposed (2). Electron transfer between N-bromosuccinimide and tetra butyl ammonium succinimidate gave 65% succinimide, and ∼10% polymer), the nature of which was determined by nuclear magnetic resonance. The build up and decay of maleimide were followed by nuclear magnetic resonance. The development of the characteristic base induced yellow-red color of the polymaleimide could be followed kinetically and the effect of additive studied. The reaction resulted in weak chemiluminescence. This supports the hypothesis that the initial step of the reaction is electron transfer, forming a cage radical ion/radical pair. N-Br bond cleavage within the cage forms a pair of succinimide radicals, which react with disproportionation to give succinimide and maleimide. The latter then undergoes predominant radical polymerization. The reaction of N-chlorosuccinimide with tetra butyl ammonium succinimidate also gave polymaleimide (40%) and succinimide (47%) (3, 4).

The crystallization and local dynamics of poly(e-caprolactone) (PCL) confined to self-ordered nanoporous alumina (AAO) were studied as a function of pore size, pore surface functionality, molecular weight and cooling/heating rate by differential scanning calorimetry (DSC), wide-angle X-ray diffraction and dielectric spectroscopy. In contrast to the bulk, PCL located inside nanoporous alumina crystallizes via several distinct nucleation mechanisms. All mechanisms display pronounced rate dependence. At low undercoolings, the usual heterogeneous nucleation of bulk PCL was suppressed at the expense of two additional mechanisms attributed to heterogeneous nucleation initiated at the pore walls. At higher undercoolings a broad peak was observed in DSC which we attribute to crystallization initiated by homogeneous nucleation. At high cooling rates, the critical nucleus size is smaller than the smallest diameter of pores. Thus, PCL is able to crystallize within the smallest pores, despite the lower degree of crystallinity. Inevitably, homogeneous nucleation is strongly coupled to the local viscosity and hence to the local segmental dynamics. Dielectric spectroscopy revealed that confinement affected both the rate of segmental motion with a lowering of the glass temperature as well as a broader distribution of relaxation times.

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